package com.webserver.core;

import com.webserver.annotation.Controller;
import com.webserver.annotation.RequestMapping;

import java.io.File;
import java.lang.reflect.Method;
import java.net.URISyntaxException;
import java.util.HashMap;
import java.util.Map;

/**
 * 保存所有请求与对应的业务处理关系
 */
public class HandlerMapping {
    /*
    key:请求路径(path)
    value:处理该请求的业务类及对应方法

    例如：
    key:/myweb/reg
    value:MethodMapping{
             controller:UserController
             method:reg()
             }
     */
    private static Map<String,MethodMapping> mapping=new HashMap<>();

    static {
        initMapping();
    }

    private static void initMapping() {
        /*
        扫描com.webserver.controller包中的所有类，并将所有被注解@Controller
        的类实例化，然后将@RequestMapping标注的方法获取，并将这两项以一个
        MethodMapping表示。最终将@RequestMapping注解传递的参数(请求路径)作为
        key,将这个MethodMapping作为value保存到mapping这个map中。
         */
        try {
            File dir = new File(
                    HandlerMapping.class.getClassLoader().getResource
                            ("./com/webserver/controller").toURI()
            );
            File[] subs = dir.listFiles(f -> f.getName().endsWith(".class"));
            for (File sub : subs) {
                String fileName = sub.getName();
                String className = fileName.substring(0, fileName.indexOf("."));
                Class cls = Class.forName("com.webserver.controller." + className);

                //判断该类是否被注解@Controller标注了
                if (cls.isAnnotationPresent(Controller.class)) {
                    System.out.println(className + "类被@Controller标注了...");
                    Object controller = cls.newInstance();//实例化这个Controller

                    //获取其定义的所有方法
                    Method[] methods = cls.getDeclaredMethods();
                    for (Method method : methods) {
                        //判断该方法是否被注解@RequestMapping标注了
                        if (method.isAnnotationPresent(RequestMapping.class)) {
                            System.out.println(method.getName() + "方法被@RequestMapping标注了！");
                            //通过注解获取该方法对应的请求路径（从注解上的参数获取）
                            RequestMapping rm = method.getAnnotation(RequestMapping.class);
                            String path = rm.value();
                            MethodMapping mm = new MethodMapping(controller, method);
                            mapping.put(path, mm);
                        }
                    }
                }
            }
        } catch (URISyntaxException | ClassNotFoundException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }
        System.out.println(mapping.size());
    }

    /**
     * 根据请求路径获取对应的业务处理类
     * @param path
     * @return
     */
    public static MethodMapping getMethodMapping(String path){
        return mapping.get(path);
    }

    public static class MethodMapping{
        //某个Controller实例
        private Object controller;
        //对应的业务处理方法
        private Method method;

        public MethodMapping(Object controller, Method method) {
            this.controller = controller;
            this.method = method;
        }

        public Object getController() {
            return controller;
        }

        public void setController(Object controller) {
            this.controller = controller;
        }

        public Method getMethod() {
            return method;
        }

        public void setMethod(Method method) {
            this.method = method;
        }
    }

    public static void main(String[] args) {}
}
